Random variables

These functions can be entered from the PopTools menu, or (in PopTools
version 1.2 and above) through the standard Excel function wizard (the button
that looks like this ). There are two
versions of each formula, but you should always use the direct DLL versions,
which are fast. The older versions are retained for backwards compatibility. The
formula names of the direct DLL versions are preceded by a lowercase
"d", as shown in the example below for a Poisson random variable with
parameter 5.

Formula

Type

Type of result

=dPoisson(5)

Direct DLL version (fast)

Volatile

=Poisson(5).

VBA version (slow)

Volatile

A new feature in PopTools version 1.4 and above is the ability to enter
random variables as arrays. These functions make a single call to the DLL and
are generally much faster than the versions entered in just a single cell. The
array versions take have an "A" appended to their name and take an
extra argument specifying how many variables to generate. For example, the
following generates 1000 variables from the Poisson distribution with parameter
5: